O.K., so I use a Mr. Beer Kit... Sue me! But my brew is still foaming/bubbling just a little bit (i.e. like a very old weak nearly stale Pepsi). At the front of the see-through brewer I see about a tablespoons full of bubbles. Dare I bottle, or am I going to glass everywhere.

Ok, I won't sue...I used to use a Mr. Beer myself Of course, the best way to tell would be to use a hydrometer. But I know the kit didn't come with one, so....here's what I used to do. During fermentation krausen (the foam) will build on the top of the brew. It will start slowly and then peak, afterwards it'll die back down indicating main fermentation is pretty much over. You'll know you've reached this point if you notice small clusters of foam at the top of the brew rather than an overall thick layer across the entire fermenter. At this point I used to give it another week before I'd bottle as a precautionary measure. Total time in the fermenter was about 2 weeks. As a side note, if you have a homebrew store around you may want to pay them a visit--at least for a hydrometer. However, you can get a basic brewing kit for about the same price you paid for the Mr. Beer, and you'd be able to double your output capacity to 5 gals.
Hope this helps. Cheers!